Machines for coating sheet material with adhesive or the like



1968 D. MARTIN 3,412,708

MACHINES FOR COATING SHEET MATERIAL WITH ADHESIVE OR THE LIKE Filed Dec. 5, 1966 5 Sheets-Sheet 1 FIG.

Hrrys.

Nov. 26, 1968 D. MARTIN 3,412,708 MACHINES FOR COATING SHEET MATERIAL WITH ADHESIVE OR THE LIKE Filed Dec. 5, 1966 5 Sheets-Sheet 2 firrys.

United States Patent 3,412,708 MACHINES FOR COATING SHEET MATERIAL WITH ADHESIVE OR THE LIKE Donald Martin, Ros Nuala, Brookfield Lawn, The Lough, Cork, Ireland Filed Dec. 5, 1966, Ser. No. 599,164 Claims priority, application Ireland, Dec. 7, 1965, 1,279/65; Feb. 18, 1966, 171/66 3 Claims. (Cl. 118-261) ABSTRACT OF THE DISCLOSURE Coating equipment comprises a pair of upper and lower rolls and a doctor blade adjacent the upper roll. The lower roll is vertically movable and is continuously urged upwardly by a counterweight suspended from chains that are reeved over sprockets.

This invention concerns a machine for applying a coating of adhesive or the like to one side of sheet material; the machine is intended for use more particularly in connection with the lamination of plastic sheet material such as foamed polyurethane, which involves the employment of a quick setting adhesive, but it may also be used in connection with the coating of other she t materials generally with adhesives or other liquid or spreadable substances.

The main problem involved is to apply to one surface of sheet material of any required thickness a desired quantity of adhesive or the like in an even film, and without the machine itself becoming clogged with the adhesive substance. This problem has proved particularly ditficult to solve in cases whereby the coating material is a quick setting adhesive. A further problem arises in providing a machine which will apply the desired coating to one or more strips of the surface of predetermined width while leaving the remainder of the surface uncoated.

These problems are solved by the machine according to the invention, wherein the adhesive or the like is adapted to be applied to the upper surface of the sheet material by means of a roller beneath which the sheet is traversed the coating material being applied first to the surface of the roller by the aid of a doctor adjustably mounted with its operative edge in contact with, or closely adjacent to, the surface of the roller and arranged to provide together with said surface a substantially V-shaped trough to receive the coating material the ends of said trough being closed by stopper blocks loosely placed in the trough and shaped to conform to the contours of the sides of the V-shaped trough. By adjustment of the doctor the thickness of the film of the coating material which passes from the trough upon the circumferential surface of the roller as said surface moves downwards past the doctor on rotation of the roller may be precisely predetermined. At its lowest point the surface of the roller makes contact with the underlying surface of the sheet material, which is preferably advanced at the same speed as the periphery of the roller with which it is in contact, and the coating material is thus transferred to the surface of the sheet. Very little coating material remains upon the surface of the roller after contact with the underlying surface of the sheet material, and the speed of rotation of the roller is arranged so that before any such remnants of coating material can set they will have been carried on the roller surface to the position where the doctor is located and a fresh quantity of the coating material will be entrained to continue the sequence of operation.

A machine according to the invention preferably comprises an upper roller and a lower roller between which the material to be coated is adapted to be passed, said roller being relatively movable in a vertical plane, means being provided for pressing one of the rollers towards the "ice other, means for driving the rollers in opposite directions at substantially the same peripheral speed, and a doctor associated with the upper roller so as to be adapted to provide in conjunction with the adjacent surface of the roller a substantially V-shaped trough to receive the liquid coating material and from the bottom of which a film of the liquid is adapted to be entrained by the surface of the roller moving downwardly in relation to the adjacent operative edge of the doctor for deposition upon the surface of the sheet material passes between the rollers. Preferably the lower roller is movable vertically in the machine frame and an upward force is applied to said rollers by the aid of one or more counterweights. The arrangement ensures that a constant pressure is exerted between the rollers.

A simple construction of a machine according to the invention is hereinafter described with reference to the accompanying drawings, wherein:

FIG. 1 is an elevation of the machine, the doctor and other parts being removed for the sake of clarity,

FIG. 2 is a plan of the machine,

FIG. 3 is an end elevation of the machine to a larger scale,

FIGS. 4 and 5 respectively are a side elevation and a front elevation showing to an enlarg d scale the support for a doctor,

FIGS. 6 and 7 are respectively an end elevation and plan of one form which the doctor may advantageously take.

Referring to the drawings, the frame of the machine consists essentially of two end frame portions 1, 1 made of channel-shaped members rigidly spaced apart in parallel arrangement by means of channel bracing members 2. At the upper end of the frame portions 1 are mounted bearings 3 for the upper roller 4, the spindle of which at one end carries a sprocket wheel 5 in the plane of the adjacent frame portion. The lower roller 6 is arranged immediately below the upper roller 4, being supported at each end by vertically movable bearing plates 7 each welded to the upper end of a guide bar 8, the lower portion of which passes between guide rollers 9 carried by cross members 10 of the frame portions 1. The guide bars 8 are thus vertically guided. They are urged in an upward direction by a counter-weight system consisting of a layshaft 11 rotatably mounted in brackets 12 and having two pairs of sprockets wheels 13, 13 and 14, 14 secured thereon. Chains 15 partially lapped in one direction over the respective sprocket wheel 13 and attached at one end thereto are secured at the other end to a lateral extension 16 of the adjacent guide bar 8, while chains 17 are attached at one end to the respective sprocket wheels 14, partially lapped in the opposite direction over said sprocket wheel and attached at the other end to a counterweight 18. The latter thus applies a torque to the shaft 11 in one direction while the weight of the guide bars 8 and the roller 6 carried thereby applies a torque in the opposite direction to said shaft. The counterweight 18 may be chosen so as to cause the roller 6 to be pressed upwards and into contact with the roller 4 with any desired pressure. In order to vary this pressure the weight 18 may be readily charged or additional weights may be added to the weight 18 as may be desired. At the same time the roller 6 is permitted to yield when the sheet material to be coated is passed between the rollers 4, 6, the pressure exerted between the rollers remaining constant and the drive being in no way interfered with.

The rollers 4 and 6 are rotated in opposite directions at the same speed by a driving chain 19 passing over the sprocket wheel 5, over a similar sprocket wheel 20 secured to the spindle of roller 6, over a tensioning pulley 21 and a driving sprocket wheel 22 of a motor 23 as shown in FIG. 3. The pulley 21 is carried upon a pivoted arm 24 provided with a tensioning spring so as to maintain a desired tension upon the driving chain 19 at all times.

The doctor which is a most important element in the successful operation of the machine consists of a steel strip 26 of L-shaped cross-section the rectangular ends 26' of which are slotted to provide sockets to receive the ends of arms 27 pivotally mounted at 28 on the frame portions 1 (FIG. 3). One edge 29 of the strip 26 serves as the operative edge and is located very close to, if not in contact with, the surface of the roller 4 when the doctor is in position for use. The doctor itself is firml clamped to the pivoted arms 27 by means of screws 30 in bridge pieces 31 extending over the slots in the doctor ends 26', and precisely positioned therein by adjusting screws 32, while the position of the operative edge 29 of the doctor in relation to the adjacent roller surface may be finely adjusted by collared screws 33 the threaded ends of which are of reduced diameter so as to pass freely through apertures 34 in lugs 35 on the arms 27 and into screw threaded apertures 36 of lugs 37 welded to the frame portions 1. If the screws 33 are removed the doctor may be swung outwards into the position shown by broken lines in FIG. 3, for example, for cleaning.

Though held by the screws 33 doctor 26 tends to press away from the roller 4 under its own Weight to which is added the weight of stopper members 38, advantageously made of, or faced with brass, shaped to conform to the contour of the inclined doctor surface of the one hand and the adjacent surface of roller 4 on the other hand. The members 38 rest freely upon said doctor surface and roller surface and serve to seal the ends of the trough 40, thus provided between the upper surface of the doctor 26 and the adjacent surface of the roller 4. The trough 40 is substantially V-shaped in cross-section and serves as a reservoir for a supply of the liquid coating material.

By adjusting the stopper member 38 laterally along the trough 40, as seen more clearly from FIG. 2, the width of the coating to be applied to the material passed between the rollers 4 and 8 may be precisely determined. It is also possible to apply the coating material in two or more separate strips by the use of additional stopper members, such as the member 38 indicated by broken lines in FIG. 2, to enable the trough 40 to be divided into a plurality of trough sections some of which may be supplied With coating material while the remainder are left empty.

In order to support the sheet material being fed to the machine, supporting plates 41 and rollers 42 may be provided, carried at each end on laterally extending bracket arms 43 bolted to the bearing plates 7.

The manner of operation of the machine will be obvious from the foregoing. By means of the machine a coating of adhesive or other liquid may be applied to the surface of any sheet material, either uniformly all over, or in strips of limited width, as desired, irrespective of the thickness of the sheet and with ready control of the thickness of the applied coating. The machine is highly eifective in dealing with the difficult problem of applying a quick-setting adhesive to such materials as foamed polyurethane. i

It will also be evident that the details of construction of the machine may be varied Without departing from the invention. In particular the arrangement for biasing the movably mounted roller may be carried out in various ways. The movement of the lower roller may be arranged to be activated in known manner by pneumatic or electric servomechanism to ensure that its lower roller always floats with equal upward biasing forces applied to opposite ends thereof. It would also be possible to arrange for the upper roller together with the associated doctor to be capable of vertical movement, the lower roller being maintained in fixed bearings.

I claim:

1. A machine for applying a liquid coating to one surface of sheet material comprising a frame, a coatapplying roller disposed horizontally in bearings carried by said frame, means for traversing the sheet material below and in contact with said roller, a doctor mounted adjacent to said roller with its operative edge extending longitudinally of and in proximity to the circumferential surface of the roller said doctor being inclined upwardly away from said surface so as to provide a V-shaped trough, means for adjusting said doctor to vary the width of the gap between said edge and surface, means for rotating the roller so as to move the roller surface past said edge in a downward direction, a second roller located below said coat-applying roller, bearings for supporting said second roller, guide means supporting said bearings at each end of the frame with freedom of vertical movement, counterweight means for applying upward biasing force to said bearings to urge said second roller into contact with said coat-applying roller, and means to rotate said second roller at the same peripheral speed as said coatapplying roller.

2. A machine as claimed in claim 1, said counterweight means comprising an elongated shaft rotatably mounted parallel to said second roller, an elongated counterweight parallel to said shaft, sprockets secured on said shaft and spaced apart lengthwise of the shaft, chains reeved over said sprockets, at least some of said chains having lower ends in a unitary assembly with said second roller, at least some of said chains having lower ends secured to said elongated counterweight at spaced points therealong.

3. A machine as claimed in claim 1, and stopper blocks disposed in said trough and movable longitudinally along said trough to constitute the ends of the trough.

References Cited UNITED STATES PATENTS 443,576 12/1890 Hawks 1l8242 X 2,213,117 8/1940 Blackmore 118-261 X 2,387,929 10/1945 Monroe 118261 X 2,485,737 10/ 1949 Jacoby 118-242 3,169,082 2/ 1965 Krikorian.

CHARLES A. WILLMUTH, Primary Examiner.

R. I. SMITH, Assistant Examiner. 

